Search for agriculturally important microorganisms from Terai-Dooars regions of North Bengal, analysis of their diversity and application for plant growth promotion and disease management
Dey, P. L.; Chakraborty, B. N.; Saha, A.
Studies on microbial diversity and their importance as bioprotector and biofertilizer may signify the economically agricultural based regions. Microorganisms were isolated from soil sample of forest, riverine beds and rhizosphere of different crops using various selective medium and isolation soil plating technique. Microbial population determined in soils ranged between 5×103 and 15×104 cfu in case of fungi and 10×106 cfu and 30×106 cfu in case of bacteria. Isolates were characterized for H2S production, phosphate solubilization, starch hydrolysis, casein hydrolysis, chitin degrading, siderophore production, catalase production, protease production, urease production, cellulase production and indole production. On the basis of these positive activities of phosphate solubilizing fungi (Aspergillus niger, A. melleus, A. clavatus), phosphate solubilizing bacteria (Bacillus pumilus) and phosphate solubilizing actinomycetes (Streptomyces gresious) were evaluated for the growth promotion ofGlycine max, Vigna radiata and Cicer arietinum. In vitro tests of potential biocontrol agents (Trichoderma) showed significant inhibition against different fungal pathogens. Application of potential BCA isolates of Trichoderma harzianum singly and jointly suppressed sclerotial blight incidence of Vigna radiata and Phaseolous vulgaris in greenhouse and field conditions by enhancing key defense enzymes like chitinase, β 1-3 glucanase, and peroxidase, which were confirmed by immunological assays. The diversity of selective potential isolates of PSF and BCA were analysed using RAPD-PCR.